Optimal feedforward control of active magnetic bearing system subject to base motion

This paper is concerned with application of active magnetic bearing (AMB) system to levitate the elevation axis of an electro-optical sight mounted on a moving vehicle. In such a system, it is desirable to retain the elevation axis within predetermined air-gap while the vehicle is moving. An optimal base acceleration feedforward control is proposed to reduce the base motion response. In the consideration of the inaccuracy of the system model, a filtered-x least-mean-square algorithm is used to estimate the frequency response function of the feedforward control which cancels base motions. The frequency response function is fitted to an optimal feedforward control. Experimental results demonstrate that the proposed control reduces the air-gap deviation to 27.7% that by the feedback control alone.